In advanced technology it is necessary to join metal and ceramic components, e.g. in making metal- or ceramic-matrix composites, in electronic packaging or in vacuum sealing. Solid state diffusion bonding, in addition to bonding utilizing adhesive and by brazing, is a recent method for bonding metals to ceramics. Many attempts, including surface modification (U.S. Pat. Nos. 4,542,073 and 4,824,008), phase transformation (U.S. Pat. No. 4,470,538), and insertion of a layer of a mixture consisting of oxides and metals (U.S. Pat. Nos. 2,800,710 and 4,763,828), have been made to improve the bonding strength between metals and ceramics.
U.S. Pat. No. 4,050,956 describes a method of directly bonding metals and ceramics involving positioning these in abutting relationship and heating in air at a temperature ranging from about 800.degree. C. to a maximum set by the melting point of the metal. This procedure produces strengths that range widely from very low values, such as 0.2 inch-pounds torque up to high values such as 108 inch-pounds of torque.